My Piece of Dirt

Zone 8 Gardening

Wet and Humid = Fungus

on August 14, 2014
powder mildew

powder mildew

Early/ Late Blight are fungal diseases that affect plants in the nightshade family: tomatoes, potatoes, eggplant, peppers and others.  Blight appears during periods of high humidity or rainfall.  Darks brown/black spots appear and are then encircled by yellow.

Black spot is a “soil borne’ fungi or bacteria.

Powder Mildew, (blanket name for many species of fungi) is a fungal spore spread by wind and over-wintering in plants and in plant debris.

Yellow Leaf can be caused by lack of sunshine, water and/or nitrogen.  If the bottom leaves turn yellow and the problem continues toward the top of the plant–particularly in the cabbage/ broccoli family– the plants need high nitrogen (but low phosphorus) fertilizer of blood meal.  Blood Meal is a quick nitrogen fix for yellowing leaves.   Or it can be caused by fungi or bacteria.  If you eliminate the questions of sunshine, water and nitrogen, it is safe to assume fungi or bacteria are the real problem.

Leaf Curl is a plant disease caused by a fungus.  (Special Note:  tomato plants can curl their leaves any time that they are unhappy about anything:  too much water, not enough water, too much sun, not enough sun, too much fertilizer, not enough fertilizer, etc.  As long as the leaves are still green, it may not be a fungi.)

Bacteria are not fungi, but I include it here because the cure is the same.  Bacteria generally come from the poop or spit of bad bugs. (Who cares what end it comes from?)

More Fungi = Brown Patch in Turf grass, Canker, Down Mildew, Damping Off of seedlings, Club Root, Bottom Rot, Anthracnose, Dutch Elm Disease, Dry Rot, Crown Wart, Potato Wart, Plant Wilting, Apple Scab, Rust, and etc, etc. Mind boggling and all fungi. Think of fungi as plants that grown on your plants.  Or think of them as germs.

But rather than memorize all these names, just remember this:

There is no cure.  There is only prevention and eradication.

Do not strain your brain or stretch your pocketbook.

An Ounce of Prevent

  • Dry heads & wet feet
  • Sun
  • Wind — plant in the middle of the yard, not against a structure.
  • Aeration — after mucky weather, FAN IT.  Particularly the underside of leaves and the main stem.
  • Mulch — use mulch to prevent backsplash.
  • Periodic Removal and refreshment of mulch extremely beneficial and cures other problems too.  (Not hard to do:  rake it out, thin it over the yard, sun dry it or a day or two, mow it back up and reuse.)  However, do not reuse old mulch when there has been a ‘problem.’
  • Control —  control plant so that limbs do not intertwine or cross over and do not allow leaves to bunch.  Train plants to grow up the trellis, not run along ground level.
  • Remove fallen fruit.


  • Pruning  — If a leaf turns color prune it. It does not matter why it turned color; it is not doing its photosynthesis thing anymore.  It will NOT recover.  It will be a source of weakness.  Assume that this leaf is ‘germy.’ Extract it without touching any other part of the plant. Sterilize equipment.  Do not put diseased leaves in compost pile.
  • Repeat problem areas:  Treat with a spray bottle of:  1 teaspoon of baking soda and 1 squirt of dish liquid.  Warning:  Baking soda can burn plants.
  •  Serious cases/ Or if disease is hopping from plant to plant:

Burn or trash plants and the mulch too.  Sun Dry Ground and Till. Do not be fast on the draw to replant in this spot. If you have the proper set-up to completely burn this material without using an accelerant, you can use it as pot ash.










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